The detection of cytogenetic anomalies is important for the diagnosis and prognosis of hematological malignant diseases. Karyotypes of 32 Armenian patients with chronic myeloid leukemia have been studied for the presence of Philadelphia (Ph) chromosome resulting from translocation t(9;22)(q34;q11) by means of conventional karyotype analysis (CK) and fluorescence in situ hybridization (FISH) in the bone marrow and/or peripheral blood specimens. In our study application of metaphase or interphase FISH in chronic myeloid leukemia patients permitted to confirm and improve the results of conventional cytogenetic analysis.